Control mechanism for vibra harps



March 21, 1933. w 1,902,614

CONTROL MECHANISM FOR VIBRA HARPS Filed Oct. 1, 1931 2 Sheets-Sheet lJNVENIUR E :22? 0:23 NEJHS'.

March 21, 1933. H A BOWER 1,902,614

CONTROL MECHANISM FOR VIBRA HARPS Filed Oct. 1, 1931 2 Sheets-Sheet 2 a4a3 3 2a a;

J W 36 ii 1M 37 24 W E IE5- Patented Mar. 21, 1933 UNITED STATES PATENTOFFICE CONTROL MECHANISM FOR VIIBRA HARPS Application filed October 1,1931.

In vibra-harps a vibratile sound is given to the notes, usually byvibrators which operate in or adjacent the resonators. These vibratorsusually rotate and give a tremolo 5 effect to the sound, beingreproduced from the resonators. Usually, with this type of instrumentthere is no means provided for controlling the rate of the tremolovibration and, therefore, the instrument has decided limitations in itsmusical quality and the effects which a musician may obtain from such aninstrument are quite decidedly limited.

An object and feature of my invention is a constructionby'which themusician playing a resonant harp instrument of the xylophone type havingresonators may control a tremolo or vibrato of the sound of each andevery note and that he may increase or decrease the rate of the tremoloin accordance with the expression he desires to bring out in thecomposition being reproduced.

In this connection a feature of my mechanical construction giving thiscontrol is that I may obtain an instant variation from a retarded to anaccelerated tremolo and that when using vibrators of a vibra-harp typeof instrument I may obtain musical effects which are impossible in knownresonant harp types of instruments.

Another object and feature of my invention is a construction bywhich Imay manually set the controls to have a tremolo or Vibrato of a certaindefinite period and this will be the fundamental period which may bechanged by increasing the rate.

Another object and feature of my construction is a setting device forthe control mechanism which may be readily shifted to change the rate ofthe tremolo or vibrato of the resonators and that the rate so adjustedmay be maintained. In this connection I have a plurality of differentadjustment features allowing setting for relatively fine graduations inrate of tremolo or a coarser regulation of such rate.

In constructing my invention I preferably make use of an electric motorwhich, i through a geared drive, is arranged to operate the rotatablevibrators on the'upper like vibrator.

arm on each side of the pivot.

Serial No. 566,296.

exposed mouths of the resonator tubes. Usually, the tubes are arrangedin a row, such tubes being vertical and having the vibrating keyspositioned thereabove, and a shaft extends longitudinally of each row ofresonators, such shaft being rotatable by the motor, and at eachresonator there is a disk- The rate of rotation of these vibratorscontrols the rate of the tremolo or vibrato of the sound emitted by eachresonator. My mechanism comprises a manual control devicefor changingthe speed of the motor so that the vibrators will be rotated at a lesseror a greater speed as desired by the musician. I

In the specific construction illustrated, I employ a brake system togive a resistance to the rotation of the motor, this preferably beingdone by a. rotating disk against which brake pads may press. These padsare connected to a yoke and such yoke is slidable, the yoke beingnormally under a spring pressure to give a considerable resistance orbraking effect to the rotation of the motor and, hence, maintaining thisat a relatively low speed. I provide a pivoted operating lever, suchlever having a long and a short The long arm extends in front of thekeys and in a position to be engaged by the body of the musician so thatby leaning slightly toward the instrument or away therefrom the levermay be operated. A movement of the long end of the lever toward theinstrument through the medium of tension links exerts a pull on the yokeand decreases the pressure of the brake pads on the disk and, hence,allows acceleration of the motor and, therefore, of the rate of rotationof the vibrators. I

In order that I may obtain a manual setting of the instrument, I providea fixed bracket secured to the instrument frame, and this has a screwthreaded therethrough and such screw may operate along a block attachedto the long end of the control lever, and, hence, set this lever in adesired position. to allow the motor to operate at a substantiallyconstant speed as adjusted by the musician, which speed may manifestlybe operation ofthe vibrators.

V fixed'position, do not'preve nt the musician '16 This screw isprovided with a nut lock structure so that it may be locked and thus thedesired rate of tremolo cannot be decreased beyond the limit set.

In the construction for giving readily ad'- justable changes to thespeed'of the motor and, hence, of the vibrators, which is graduated fora coarse or fine degree of. change, I

provide a bar secured to the frame of the instrument and extending;horizontally therefrom, on which bar I have a rotatablecollar, whichcollar has a series'of notches on its diiferent faces, the collar'beingheld on the bar in adjusted positions by a set screw or the like. Thecollaris provided with a series of serrations difierent distances apartin which operates a nub on the long end'of the control lever. fineadjustment of the position of this con- 'trol lever may be obtained bythe engageinent of the nub in any oneof the serrations, and byrotatingthe collar a coarse or fine may be readily made. Theseserrations, while holdingthe control lever in a from pressing inwardlyon the manual control end of such lever to further increase the speed ofthe motor by decreasing the braking pressure.

lfarious'otherv features of improvement in the art will be apparent fromthe following description taken in connection with the drawings and theclaims.

My invention is illustrated in the accompanying drawings, in which Fig;1 is a planof' a vibra-harp type of instrument equipped with myinvention, certain parts broken away;

Fig. 2 is a vertical transverse section on the line 2-2 of Fig. 1 in thedirection of the; arrows, showing the note keys, the resonators, thevibrators, and the muting bar;

Fig. 3'is a vertical transverse section on the line'38 of Figil in thedirection of the arrows, showing the electric motor and part of thecontrol and drive mechanism in elevation Fig. 4 is a vertical transversesection showing part of the brakemechanism for the motor in section; V

Fig. 5 is a vertical longitudinal section on the line 55' of Fig. 4 inthe direction of the arrows;

Fig. 6 is a plan with parts shown in sec tion of the manually operatedadjusting mechanism for the control lever; i

F g. 1s a vertical longitudinal detail section on: the l1ne 77 of Fig. 6in the direction of the arrows;

Fig; 8 is a vertical transverse section on the line 88'of Fig. 6'in thedirection of the arrows;

Fig. 9 is a vertical transverse section on Therefore a coarse or a theline 99 of 6 in the direction of the arrows.

The vibra-harps are usually made with supporting rails 11 onwhich aremounted the sound producing bars 12, these generally being formed ofmetal. ranged in two. rows and between the rows These bars, are arthereis a damper rail 13 having a feltpad ltwhich is manipulated usually by apedal, raising the felt. against one end of eachof the bars and'therebydamping their vibration. Below each bar there is a resonator tube 15 andextending along the top of each row of tubes is a rotatable shaft .16having a disk-like vibrator 17. These vibrators are ofslightly lessdiameter than the internal diameter of the'tube to allow the freerotation and if a particular note is struck the resonator resounds' tothis note giving a prolonged reproduction of suchnote and the rotatingvibrator gives a tremolo or vibrato; effect to such note. Usually theshafts 16 are operated by electric motor 18, this motor beingillustrated as having a reduction drive 19',;and a belt drive 20, to thepulleys 21"which rotate the shafts In my invention I have an extension22 fan blades 2l which blow air over the motor 7 to keep the motor.cool'. Connected to a suitable end plate 25 there is a housing 26 whichaccommodates the disk 23 and part of the fan 24. In this housing thereis a partition 27 which supports a rod 28, such rod passing through aperforation 29' in the front end wall 30 of'this housing. A collar 31 isslidabl'y mounted on the rod 28.. This collar has aprojection 32 with aperform tion 33 therethrough, through which perforation" extends a stud34 secured in place by a cotter pin 85- and to such stud there issecured a yoke 36 on each end of which there is a felt braking pad 87.The connection of this yoke by the medium ofthe stud to the collarallows the yoke to turn slightly on the axis of this stud so'that thetwo pads illustrated bear with equal pressure on the face of the brakingdisk 23. A compression spring 88 coiled on the rod 28 and bearingbetween the front plate '30 and the collar tends to thrust the collarand hence, the yoke inwardly, applying the brake with considerablepressure. p

A slidable sleeve 39 is mounted on the rod 28 outside of the housing.This is limited in its sliding movement by means of a knurled handoperated nut 40 and a lock wing nut 41. The rod 28 may readily beattached or detached through the medium offormed of two wires or rodsconnected to a lug 46 secured to the collar 31. This bracket 44 has aperforation 47 through which extends a threaded finger 48, there being ajam nut 49 to limit the movement of such finger and the finger issecured to the short end 50 of an operating lever designated generally51, which lever has a long end 52, the lever having a fulcrum at 53,such fulcrum being on a bracket 54 attached to the frame of the musicalinstrument, (note Fig. 2). This fulcrum may be adjustable on thebracket. For purposes of convenience, the long end 52' of the lever hasan arcuate section 55 and has a bolted connection 56 to an outer section57, to which outer section is added a wood pressure plate 58, this beingin a position to be engaged by the lower part of the abdomen of themusician.

' A tension spring 59 is secured to the end of the short section 50 ofthe operating lever 51 and attached as indicated at 60 to the end plate25 of the frame, thus giving an additional tension means to hold thelever with the short end inwardly and the long outer operating end 52outwardly from the sound bars of the instrument.

In the operation of this part of the instrument, the pressures of thesprings normally maintain the more or less certain pressure 011 thebraking disk and will thus maintain the motor normally running at a nor7 mal speed, this speed being fairly low so that the tremolo or vibratoeffect on the sounds from the resonators have a comparatively shortperiod. Themusi-cian playing the instrument may then, if he wishes afaster rate of tremolo or vibrato, lean against the outer end 52 of theoperating lever, thus pressing this inwardly and exerting a tension onthe link 45 and pulling outwardly on the collar 31 and, hence, releasingthe pressure that the braking pads 27 bear on the disk 23. This allowsthe motor toinstantly speed up and drive the vibrator 17 at a higherrate of speed. The amount of leverage of the lever 51 is so adjustedthat a comparatively long are of movement is necessary for the end 52 togive a small movement to the short end of the lever and thereby controlsthe motor through a wide range of speed.

A setting al'ustment for the lever 51. to set the initial brake pressureis provided by the following mechanism: A two-armed bracket or brace 61is secured to the front rail 11 of the musical instrument. This brackethas a head 62 with a threaded perforation 63 through which extends athreaded tube 64, such tube having a knurled hand wheel 65 secured toits outer end. The inner end of this tube bears against a block 66 whichhas a pressure exerting nub 67. A pair of channel-shaped guides 68 (noteFigs. 6 and 7) are secured to the block 66 and instrument.

The arcuate section 55 of the outer por- 3 tion 52 of the lever 51 has acollar '7 4 secured thereto from which there is an upwardly extendingplate 7 5, this-plate havin' a bend as indicated at 76 (note Fig. 8). Tis plate I has an elongated recess 77 into which the operating end ofthe nub 67 bears. There- 7 fore, by this construction, by operating theknurled hand wheel 65 one way or the other, the threaded tube 64 isforced inwardly or outwardly, carrying the head 66 and the nub 67 andthrough the medium. of the plate and the collar 74 moves the long end ofthe lever 51 inwardly or outwardly; The threads on the tube 64 arepreferably of a coarse pitch to give a quick adjustment. Thisadjustment'may be arranged to set the initial pressure of the brakingpads and thus allow the motor to operate at a substantially definitespeed but does not in any manner interfere with the further inwardmovement of'the lever due to inward pressure on the end 52. This givesthe musician an initial setting to produce the lowest rate of tremolo orvibrato which he desires.

'A readily releasable adjuster device 78 employs a rod 79 secured to theframe of the On such rod there is a collar 80, this being adjustable andhaving a set screw 81 to clamp such in the adjusted positions; Thiscollar has sets of serrations 82 .and 83, these being of differentdegrees of coarseness.

Any one set may be brought into a position to be engaged by an elongatednub 84 on the portion 55 of the lever 51. A compression spring 85operating between the instrument and the Washer 86 is under compressionto thrust-outwardly on the collar. The collar may, therefore, readily beadjusted to retain the control arm in any one of the serrations but yetwill allow movement of such arm in order to hold the nub 84 in a tightfit in the serrations. An abutment nut 88 is threaded on rod 7 9 andforms 'an adjustable limit to the outward movement of collar 80.

A rod 87 has a wedging end accommodated in a deep socket 7 9 in rod 79,and the opposite end is provided with a tension spring 89 connected tothe part 55 of the lever 51. It will be seen, therefore, that-byrotating the collar different types of-serrations may be brought intoengagement with the nub and that various degreesof removement ofthc bodyof the musician,.w-ith-' out inter-feringwith the operation ot thedamper rail 13 (which is actuated by a foot pedali). ,A'slight movementof the body of the. musician to? or from thetlreys gives a widevariation tothe tremolo orvibrato effects.

' Various chances ma. be-made in the features: of the Vi-nvention'without departing from the spirit or scope thereof as definedv in theappended claims.

"I claim:

1. A musci-al instrument having a porous sion means to produce musicaltones of different pitches, a tubl'ar resonator to respond to eachdifferent tone, a vibrator for each resonatorgxa driving means'tooperate said vibrators, a setting means to initially set the drivingmeans to; operate the vibrators at. a certain: predetermined.period ofvibration, and a. control means operable by the body of the player, of.the instrument to increase the rate ofdrive to decrease the period; ofvibration.

2; A musical instrument as claimed. in claim 1 havlng in. addit on an"ad usting means to regulate the control: means for -.changing' and.retainingthe driving means to operatethe vibrators at predetermined:periods of vibration, said adjusting means having a slip connection toallow operation of said control. means;

V A musical instrumentthaving a row of sound-bars to produce musicaltones by per-v cussion, a tubular resonator: to respond to each tone,-.avibrator for each. resonator, said vibrators bemg connected together tooper- I 7 claim 6, themeans to control the motor comate in unison,amotor 'to dri've'saidvibrators, a pivotally mounted control leverhaving, one end positioned to be en-gaged. by the player of' theinstrument and the other end having, an operative connection tothe motorto vary the" speed thereof whereby on operation of said: lever theplayer of the instrument may change the speed: ot the motor..

.4; A musical instrument as claimed in claim 8,. a bracket. connected tothe instrumentv and having an adjusting screw therein, meansinterengaging between said screw and the lever to position said leveri-nan initial position to give a relatively slow rate of vibration of thevibrators, said lever being movableto increase the speed of the motorand hence the. rateaof vibration. of the vibrators. I V 1 5. A musicalinstrument having a rowof percussion sound bars to-produce tones ofdifferent pitches, a tubular resonator posi-i connection to the motor tovary the speed thereof, a setting device. comprising a bracket mountedon the instrument and having ascrew threaded rod with an.interconnection between said rod andthe lever to adjust the lever to aninitial position to give a rela tively slow speed to the motor and henceto the vibrators, said lever being operable to increase the speed ofthe; motor and. hence of the vibrators, an ad usting means comprising arod secured to the lnstrumenthaving a collar with serrations adjustablymounted thereon, and means on the lever to engage said serrations toadjust the posi- 131011 of the lever independent ot the 1n1t1al settingof vthe lever, said serrations permitting movement of thelever to changethe speed of the motor and hence of the vibrators. w

V 6. A musical instrument having a series of sound bars arranged in ahorizontal supporting frame, a resonator beneath each'bar,

a: vibrator on each resonator, a motor drive to all of the vibrators tooperate same in unison, a control lever pivoted adjacent one end of thesound bar supporting frame and having an operating. end extendingsubstantially parallel to saidv frame spaced therefrom and adapted tobeengaged bythe body of the player when playing on the sound bars, andmeans actuated by said lever to control the speed of the motor and henceof the vibrators. V

7. A musical instrument as claimed in prising a brake disk actuated bythe motor, a brake pad, and aconnection fromthe levor to adjust thebrake pad in relation to the brake disk.

8. A musical instrument as claimed in claim '6, the sound bar,supporting frame 1 being adapted to engage said lever to adjust thelever tov an initial position to determine the lowest vibration of thevibrators, the lever being operable by the movement of the body of aplayer to release the lever from the end of the screw-to accelerate thevibrators.

9. A musical instrument as claimed in claim 6, a releasable adjuster forthe control lever comprising a rod secured to the frame and extendingoutwardly therefrom, a collar on said rod having a series of notches,the control lever having a nub to engage in any one of the notches, saidnub and control lever being readily disengaged from said notches.

10. A musical instrument having a horizontal frame with a row ofpercussion bars extending therealong, a resonator beneath each bar, eachresonator having a rotatable vibrator, a motor having a drive to thevibrators to rotate all of the vibrators at the same speed, said motorhaving a brake disk and abrake pad to engage therewith, spring means tonormally urge the brake pad into engagement with the brake disk, acontrol lever mounted on a vertical pivot, the control end of the leverextending substantially parallel to one side of the frame and spacedtherefrom, the opposite end of the lever having a link mechanism toconnect to the brake pad to release the pressure of the brake pad andthe brake disk when said lever is pressed inwardly by the body of theinstrument player actuating such instrument and thereby varying thespeed of the motor and of the vibrators.

11. A musical instrument as claimed in claim 10, a setting adjustmentdevice comprising a bracket secured to the frame extending outwardly,said bracket having a screw operating therein, the bracket formingguides for the movement of the screw, the screw having a pointed end,and means on the. control lever to engage such end whereby the initialadjustment of the screw may regulate the pressure of the brake pad onthe brake disk.

12. A musical instrument as claimed in claim 10, a releasable adjustercomprising a rod extending outwardly from the frame and having a movablecollar thereon, a spring normally urging said collar in one direction, aclamp screw to retain the collar stationary, said collar having a seriesof transverse notches, the control lever having a nub to engage therein,and spring means to urge the nub into engagement with the notches, saidnub being readily released from the notches by a horizontal movement ofthe control lever.

13. A musical instrument as claimed in claim 10, a setting adjustmentdevice comprising a. bracket secured to the frame extending outwardly,said bracket having a screw operating therein, the bracket formingguides for the movement of the screw, the screw having a pointed end,and means on the control lever to engage such end whereby the initialadjustment of the screw may regulate the pressure of the brake pad onthe brake disk,'a releasable adjuster comprising i a rod extendingoutwardly from the frame and having a movable collar thereon, a springnormally urging said collar in one direction, a clamp screw to retainthe collar stationary, said collar having a series of transversenotches, the control lever having a nub to engage therein, and springmeans to urge the nub into engagement with the notches, said nub beingreadily released from the notches by a horizontal movement of thecontrol lever.

In testimony whereof I have signed my name to this specification.

HARRY A. BOWER.

